Daniel Blagrave was educated at Reading School and trained to be a lawyer. Daniel Blagrave's uncle was the mathematician John Blagrave of Southcote Manor, in what is now the Reading suburb of Southcote, and Daniel inherited the manor on John's death. In 1643 he permitted the Earl of Essex to use the manor as the Roundhead headquarters during the Siege of Reading. He was Recorder of Reading from 1645 to 1656 and again from 1658.

During the Commonwealth, Daniel Blagrave held various commissions and posts, and is said to have become a very wealthy man as a consequence.

On the restoration of King Charles II, Daniel Blagrave fled the country and settled at Aachen, in what is now Germany, where he died in 1668.